1/*
2 * AD5933 AD5934 Impedance Converter, Network Analyzer
3 *
4 * Copyright 2011 Analog Devices Inc.
5 *
6 * Licensed under the GPL-2.
7 */
8
9#include <linux/interrupt.h>
10#include <linux/device.h>
11#include <linux/kernel.h>
12#include <linux/sysfs.h>
13#include <linux/i2c.h>
14#include <linux/regulator/consumer.h>
15#include <linux/slab.h>
16#include <linux/types.h>
17#include <linux/err.h>
18#include <linux/delay.h>
19#include <linux/module.h>
20#include <asm/div64.h>
21
22#include <linux/iio/iio.h>
23#include <linux/iio/sysfs.h>
24#include <linux/iio/buffer.h>
25#include <linux/iio/kfifo_buf.h>
26
27#include "ad5933.h"
28
29/* AD5933/AD5934 Registers */
30#define AD5933_REG_CONTROL_HB		0x80	/* R/W, 2 bytes */
31#define AD5933_REG_CONTROL_LB		0x81	/* R/W, 2 bytes */
32#define AD5933_REG_FREQ_START		0x82	/* R/W, 3 bytes */
33#define AD5933_REG_FREQ_INC		0x85	/* R/W, 3 bytes */
34#define AD5933_REG_INC_NUM		0x88	/* R/W, 2 bytes, 9 bit */
35#define AD5933_REG_SETTLING_CYCLES	0x8A	/* R/W, 2 bytes */
36#define AD5933_REG_STATUS		0x8F	/* R, 1 byte */
37#define AD5933_REG_TEMP_DATA		0x92	/* R, 2 bytes*/
38#define AD5933_REG_REAL_DATA		0x94	/* R, 2 bytes*/
39#define AD5933_REG_IMAG_DATA		0x96	/* R, 2 bytes*/
40
41/* AD5933_REG_CONTROL_HB Bits */
42#define AD5933_CTRL_INIT_START_FREQ	(0x1 << 4)
43#define AD5933_CTRL_START_SWEEP		(0x2 << 4)
44#define AD5933_CTRL_INC_FREQ		(0x3 << 4)
45#define AD5933_CTRL_REPEAT_FREQ		(0x4 << 4)
46#define AD5933_CTRL_MEASURE_TEMP	(0x9 << 4)
47#define AD5933_CTRL_POWER_DOWN		(0xA << 4)
48#define AD5933_CTRL_STANDBY		(0xB << 4)
49
50#define AD5933_CTRL_RANGE_2000mVpp	(0x0 << 1)
51#define AD5933_CTRL_RANGE_200mVpp	(0x1 << 1)
52#define AD5933_CTRL_RANGE_400mVpp	(0x2 << 1)
53#define AD5933_CTRL_RANGE_1000mVpp	(0x3 << 1)
54#define AD5933_CTRL_RANGE(x)		((x) << 1)
55
56#define AD5933_CTRL_PGA_GAIN_1		(0x1 << 0)
57#define AD5933_CTRL_PGA_GAIN_5		(0x0 << 0)
58
59/* AD5933_REG_CONTROL_LB Bits */
60#define AD5933_CTRL_RESET		(0x1 << 4)
61#define AD5933_CTRL_INT_SYSCLK		(0x0 << 3)
62#define AD5933_CTRL_EXT_SYSCLK		(0x1 << 3)
63
64/* AD5933_REG_STATUS Bits */
65#define AD5933_STAT_TEMP_VALID		(0x1 << 0)
66#define AD5933_STAT_DATA_VALID		(0x1 << 1)
67#define AD5933_STAT_SWEEP_DONE		(0x1 << 2)
68
69/* I2C Block Commands */
70#define AD5933_I2C_BLOCK_WRITE		0xA0
71#define AD5933_I2C_BLOCK_READ		0xA1
72#define AD5933_I2C_ADDR_POINTER		0xB0
73
74/* Device Specs */
75#define AD5933_INT_OSC_FREQ_Hz		16776000
76#define AD5933_MAX_OUTPUT_FREQ_Hz	100000
77#define AD5933_MAX_RETRIES		100
78
79#define AD5933_OUT_RANGE		1
80#define AD5933_OUT_RANGE_AVAIL		2
81#define AD5933_OUT_SETTLING_CYCLES	3
82#define AD5933_IN_PGA_GAIN		4
83#define AD5933_IN_PGA_GAIN_AVAIL	5
84#define AD5933_FREQ_POINTS		6
85
86#define AD5933_POLL_TIME_ms		10
87#define AD5933_INIT_EXCITATION_TIME_ms	100
88
89struct ad5933_state {
90	struct i2c_client		*client;
91	struct regulator		*reg;
92	struct delayed_work		work;
93	unsigned long			mclk_hz;
94	unsigned char			ctrl_hb;
95	unsigned char			ctrl_lb;
96	unsigned			range_avail[4];
97	unsigned short			vref_mv;
98	unsigned short			settling_cycles;
99	unsigned short			freq_points;
100	unsigned			freq_start;
101	unsigned			freq_inc;
102	unsigned			state;
103	unsigned			poll_time_jiffies;
104};
105
106static struct ad5933_platform_data ad5933_default_pdata  = {
107	.vref_mv = 3300,
108};
109
110static const struct iio_chan_spec ad5933_channels[] = {
111	{
112		.type = IIO_TEMP,
113		.indexed = 1,
114		.channel = 0,
115		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
116			BIT(IIO_CHAN_INFO_SCALE),
117		.address = AD5933_REG_TEMP_DATA,
118		.scan_index = -1,
119		.scan_type = {
120			.sign = 's',
121			.realbits = 14,
122			.storagebits = 16,
123		},
124	}, { /* Ring Channels */
125		.type = IIO_VOLTAGE,
126		.indexed = 1,
127		.channel = 0,
128		.extend_name = "real",
129		.address = AD5933_REG_REAL_DATA,
130		.scan_index = 0,
131		.scan_type = {
132			.sign = 's',
133			.realbits = 16,
134			.storagebits = 16,
135		},
136	}, {
137		.type = IIO_VOLTAGE,
138		.indexed = 1,
139		.channel = 0,
140		.extend_name = "imag",
141		.address = AD5933_REG_IMAG_DATA,
142		.scan_index = 1,
143		.scan_type = {
144			.sign = 's',
145			.realbits = 16,
146			.storagebits = 16,
147		},
148	},
149};
150
151static int ad5933_i2c_write(struct i2c_client *client,
152			      u8 reg, u8 len, u8 *data)
153{
154	int ret;
155
156	while (len--) {
157		ret = i2c_smbus_write_byte_data(client, reg++, *data++);
158		if (ret < 0) {
159			dev_err(&client->dev, "I2C write error\n");
160			return ret;
161		}
162	}
163	return 0;
164}
165
166static int ad5933_i2c_read(struct i2c_client *client,
167			      u8 reg, u8 len, u8 *data)
168{
169	int ret;
170
171	while (len--) {
172		ret = i2c_smbus_read_byte_data(client, reg++);
173		if (ret < 0) {
174			dev_err(&client->dev, "I2C read error\n");
175			return ret;
176		}
177		*data++ = ret;
178	}
179	return 0;
180}
181
182static int ad5933_cmd(struct ad5933_state *st, unsigned char cmd)
183{
184	unsigned char dat = st->ctrl_hb | cmd;
185
186	return ad5933_i2c_write(st->client,
187			AD5933_REG_CONTROL_HB, 1, &dat);
188}
189
190static int ad5933_reset(struct ad5933_state *st)
191{
192	unsigned char dat = st->ctrl_lb | AD5933_CTRL_RESET;
193
194	return ad5933_i2c_write(st->client,
195			AD5933_REG_CONTROL_LB, 1, &dat);
196}
197
198static int ad5933_wait_busy(struct ad5933_state *st, unsigned char event)
199{
200	unsigned char val, timeout = AD5933_MAX_RETRIES;
201	int ret;
202
203	while (timeout--) {
204		ret =  ad5933_i2c_read(st->client, AD5933_REG_STATUS, 1, &val);
205		if (ret < 0)
206			return ret;
207		if (val & event)
208			return val;
209		cpu_relax();
210		mdelay(1);
211	}
212
213	return -EAGAIN;
214}
215
216static int ad5933_set_freq(struct ad5933_state *st,
217			   unsigned reg, unsigned long freq)
218{
219	unsigned long long freqreg;
220	union {
221		__be32 d32;
222		u8 d8[4];
223	} dat;
224
225	freqreg = (u64) freq * (u64) (1 << 27);
226	do_div(freqreg, st->mclk_hz / 4);
227
228	switch (reg) {
229	case AD5933_REG_FREQ_START:
230		st->freq_start = freq;
231		break;
232	case AD5933_REG_FREQ_INC:
233		st->freq_inc = freq;
234		break;
235	default:
236		return -EINVAL;
237	}
238
239	dat.d32 = cpu_to_be32(freqreg);
240	return ad5933_i2c_write(st->client, reg, 3, &dat.d8[1]);
241}
242
243static int ad5933_setup(struct ad5933_state *st)
244{
245	__be16 dat;
246	int ret;
247
248	ret = ad5933_reset(st);
249	if (ret < 0)
250		return ret;
251
252	ret = ad5933_set_freq(st, AD5933_REG_FREQ_START, 10000);
253	if (ret < 0)
254		return ret;
255
256	ret = ad5933_set_freq(st, AD5933_REG_FREQ_INC, 200);
257	if (ret < 0)
258		return ret;
259
260	st->settling_cycles = 10;
261	dat = cpu_to_be16(st->settling_cycles);
262
263	ret = ad5933_i2c_write(st->client,
264			AD5933_REG_SETTLING_CYCLES, 2, (u8 *)&dat);
265	if (ret < 0)
266		return ret;
267
268	st->freq_points = 100;
269	dat = cpu_to_be16(st->freq_points);
270
271	return ad5933_i2c_write(st->client, AD5933_REG_INC_NUM, 2, (u8 *)&dat);
272}
273
274static void ad5933_calc_out_ranges(struct ad5933_state *st)
275{
276	int i;
277	unsigned normalized_3v3[4] = {1980, 198, 383, 970};
278
279	for (i = 0; i < 4; i++)
280		st->range_avail[i] = normalized_3v3[i] * st->vref_mv / 3300;
281
282}
283
284/*
285 * handles: AD5933_REG_FREQ_START and AD5933_REG_FREQ_INC
286 */
287
288static ssize_t ad5933_show_frequency(struct device *dev,
289					struct device_attribute *attr,
290					char *buf)
291{
292	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
293	struct ad5933_state *st = iio_priv(indio_dev);
294	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
295	int ret;
296	unsigned long long freqreg;
297	union {
298		__be32 d32;
299		u8 d8[4];
300	} dat;
301
302	mutex_lock(&indio_dev->mlock);
303	ret = ad5933_i2c_read(st->client, this_attr->address, 3, &dat.d8[1]);
304	mutex_unlock(&indio_dev->mlock);
305	if (ret < 0)
306		return ret;
307
308	freqreg = be32_to_cpu(dat.d32) & 0xFFFFFF;
309
310	freqreg = (u64) freqreg * (u64) (st->mclk_hz / 4);
311	do_div(freqreg, 1 << 27);
312
313	return sprintf(buf, "%d\n", (int) freqreg);
314}
315
316static ssize_t ad5933_store_frequency(struct device *dev,
317					 struct device_attribute *attr,
318					 const char *buf,
319					 size_t len)
320{
321	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
322	struct ad5933_state *st = iio_priv(indio_dev);
323	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
324	unsigned long val;
325	int ret;
326
327	ret = kstrtoul(buf, 10, &val);
328	if (ret)
329		return ret;
330
331	if (val > AD5933_MAX_OUTPUT_FREQ_Hz)
332		return -EINVAL;
333
334	mutex_lock(&indio_dev->mlock);
335	ret = ad5933_set_freq(st, this_attr->address, val);
336	mutex_unlock(&indio_dev->mlock);
337
338	return ret ? ret : len;
339}
340
341static IIO_DEVICE_ATTR(out_voltage0_freq_start, S_IRUGO | S_IWUSR,
342			ad5933_show_frequency,
343			ad5933_store_frequency,
344			AD5933_REG_FREQ_START);
345
346static IIO_DEVICE_ATTR(out_voltage0_freq_increment, S_IRUGO | S_IWUSR,
347			ad5933_show_frequency,
348			ad5933_store_frequency,
349			AD5933_REG_FREQ_INC);
350
351static ssize_t ad5933_show(struct device *dev,
352					struct device_attribute *attr,
353					char *buf)
354{
355	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
356	struct ad5933_state *st = iio_priv(indio_dev);
357	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
358	int ret = 0, len = 0;
359
360	mutex_lock(&indio_dev->mlock);
361	switch ((u32) this_attr->address) {
362	case AD5933_OUT_RANGE:
363		len = sprintf(buf, "%u\n",
364			      st->range_avail[(st->ctrl_hb >> 1) & 0x3]);
365		break;
366	case AD5933_OUT_RANGE_AVAIL:
367		len = sprintf(buf, "%u %u %u %u\n", st->range_avail[0],
368			      st->range_avail[3], st->range_avail[2],
369			      st->range_avail[1]);
370		break;
371	case AD5933_OUT_SETTLING_CYCLES:
372		len = sprintf(buf, "%d\n", st->settling_cycles);
373		break;
374	case AD5933_IN_PGA_GAIN:
375		len = sprintf(buf, "%s\n",
376			      (st->ctrl_hb & AD5933_CTRL_PGA_GAIN_1) ?
377			      "1" : "0.2");
378		break;
379	case AD5933_IN_PGA_GAIN_AVAIL:
380		len = sprintf(buf, "1 0.2\n");
381		break;
382	case AD5933_FREQ_POINTS:
383		len = sprintf(buf, "%d\n", st->freq_points);
384		break;
385	default:
386		ret = -EINVAL;
387	}
388
389	mutex_unlock(&indio_dev->mlock);
390	return ret ? ret : len;
391}
392
393static ssize_t ad5933_store(struct device *dev,
394					 struct device_attribute *attr,
395					 const char *buf,
396					 size_t len)
397{
398	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
399	struct ad5933_state *st = iio_priv(indio_dev);
400	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
401	u16 val;
402	int i, ret = 0;
403	__be16 dat;
404
405	if (this_attr->address != AD5933_IN_PGA_GAIN) {
406		ret = kstrtou16(buf, 10, &val);
407		if (ret)
408			return ret;
409	}
410
411	mutex_lock(&indio_dev->mlock);
412	switch ((u32) this_attr->address) {
413	case AD5933_OUT_RANGE:
414		for (i = 0; i < 4; i++)
415			if (val == st->range_avail[i]) {
416				st->ctrl_hb &= ~AD5933_CTRL_RANGE(0x3);
417				st->ctrl_hb |= AD5933_CTRL_RANGE(i);
418				ret = ad5933_cmd(st, 0);
419				break;
420			}
421		ret = -EINVAL;
422		break;
423	case AD5933_IN_PGA_GAIN:
424		if (sysfs_streq(buf, "1")) {
425			st->ctrl_hb |= AD5933_CTRL_PGA_GAIN_1;
426		} else if (sysfs_streq(buf, "0.2")) {
427			st->ctrl_hb &= ~AD5933_CTRL_PGA_GAIN_1;
428		} else {
429			ret = -EINVAL;
430			break;
431		}
432		ret = ad5933_cmd(st, 0);
433		break;
434	case AD5933_OUT_SETTLING_CYCLES:
435		val = clamp(val, (u16)0, (u16)0x7FF);
436		st->settling_cycles = val;
437
438		/* 2x, 4x handling, see datasheet */
439		if (val > 511)
440			val = (val >> 1) | (1 << 9);
441		else if (val > 1022)
442			val = (val >> 2) | (3 << 9);
443
444		dat = cpu_to_be16(val);
445		ret = ad5933_i2c_write(st->client,
446				AD5933_REG_SETTLING_CYCLES, 2, (u8 *)&dat);
447		break;
448	case AD5933_FREQ_POINTS:
449		val = clamp(val, (u16)0, (u16)511);
450		st->freq_points = val;
451
452		dat = cpu_to_be16(val);
453		ret = ad5933_i2c_write(st->client, AD5933_REG_INC_NUM, 2,
454				       (u8 *)&dat);
455		break;
456	default:
457		ret = -EINVAL;
458	}
459
460	mutex_unlock(&indio_dev->mlock);
461	return ret ? ret : len;
462}
463
464static IIO_DEVICE_ATTR(out_voltage0_scale, S_IRUGO | S_IWUSR,
465			ad5933_show,
466			ad5933_store,
467			AD5933_OUT_RANGE);
468
469static IIO_DEVICE_ATTR(out_voltage0_scale_available, S_IRUGO,
470			ad5933_show,
471			NULL,
472			AD5933_OUT_RANGE_AVAIL);
473
474static IIO_DEVICE_ATTR(in_voltage0_scale, S_IRUGO | S_IWUSR,
475			ad5933_show,
476			ad5933_store,
477			AD5933_IN_PGA_GAIN);
478
479static IIO_DEVICE_ATTR(in_voltage0_scale_available, S_IRUGO,
480			ad5933_show,
481			NULL,
482			AD5933_IN_PGA_GAIN_AVAIL);
483
484static IIO_DEVICE_ATTR(out_voltage0_freq_points, S_IRUGO | S_IWUSR,
485			ad5933_show,
486			ad5933_store,
487			AD5933_FREQ_POINTS);
488
489static IIO_DEVICE_ATTR(out_voltage0_settling_cycles, S_IRUGO | S_IWUSR,
490			ad5933_show,
491			ad5933_store,
492			AD5933_OUT_SETTLING_CYCLES);
493
494/* note:
495 * ideally we would handle the scale attributes via the iio_info
496 * (read|write)_raw methods, however this part is a untypical since we
497 * don't create dedicated sysfs channel attributes for out0 and in0.
498 */
499static struct attribute *ad5933_attributes[] = {
500	&iio_dev_attr_out_voltage0_scale.dev_attr.attr,
501	&iio_dev_attr_out_voltage0_scale_available.dev_attr.attr,
502	&iio_dev_attr_out_voltage0_freq_start.dev_attr.attr,
503	&iio_dev_attr_out_voltage0_freq_increment.dev_attr.attr,
504	&iio_dev_attr_out_voltage0_freq_points.dev_attr.attr,
505	&iio_dev_attr_out_voltage0_settling_cycles.dev_attr.attr,
506	&iio_dev_attr_in_voltage0_scale.dev_attr.attr,
507	&iio_dev_attr_in_voltage0_scale_available.dev_attr.attr,
508	NULL
509};
510
511static const struct attribute_group ad5933_attribute_group = {
512	.attrs = ad5933_attributes,
513};
514
515static int ad5933_read_raw(struct iio_dev *indio_dev,
516			   struct iio_chan_spec const *chan,
517			   int *val,
518			   int *val2,
519			   long m)
520{
521	struct ad5933_state *st = iio_priv(indio_dev);
522	__be16 dat;
523	int ret;
524
525	switch (m) {
526	case IIO_CHAN_INFO_RAW:
527		mutex_lock(&indio_dev->mlock);
528		if (iio_buffer_enabled(indio_dev)) {
529			ret = -EBUSY;
530			goto out;
531		}
532		ret = ad5933_cmd(st, AD5933_CTRL_MEASURE_TEMP);
533		if (ret < 0)
534			goto out;
535		ret = ad5933_wait_busy(st, AD5933_STAT_TEMP_VALID);
536		if (ret < 0)
537			goto out;
538
539		ret = ad5933_i2c_read(st->client,
540				AD5933_REG_TEMP_DATA, 2,
541				(u8 *)&dat);
542		if (ret < 0)
543			goto out;
544		mutex_unlock(&indio_dev->mlock);
545		*val = sign_extend32(be16_to_cpu(dat), 13);
546
547		return IIO_VAL_INT;
548	case IIO_CHAN_INFO_SCALE:
549		*val = 1000;
550		*val2 = 5;
551		return IIO_VAL_FRACTIONAL_LOG2;
552	}
553
554	return -EINVAL;
555out:
556	mutex_unlock(&indio_dev->mlock);
557	return ret;
558}
559
560static const struct iio_info ad5933_info = {
561	.read_raw = &ad5933_read_raw,
562	.attrs = &ad5933_attribute_group,
563	.driver_module = THIS_MODULE,
564};
565
566static int ad5933_ring_preenable(struct iio_dev *indio_dev)
567{
568	struct ad5933_state *st = iio_priv(indio_dev);
569	int ret;
570
571	if (bitmap_empty(indio_dev->active_scan_mask, indio_dev->masklength))
572		return -EINVAL;
573
574	ret = ad5933_reset(st);
575	if (ret < 0)
576		return ret;
577
578	ret = ad5933_cmd(st, AD5933_CTRL_STANDBY);
579	if (ret < 0)
580		return ret;
581
582	ret = ad5933_cmd(st, AD5933_CTRL_INIT_START_FREQ);
583	if (ret < 0)
584		return ret;
585
586	st->state = AD5933_CTRL_INIT_START_FREQ;
587
588	return 0;
589}
590
591static int ad5933_ring_postenable(struct iio_dev *indio_dev)
592{
593	struct ad5933_state *st = iio_priv(indio_dev);
594
595	/* AD5933_CTRL_INIT_START_FREQ:
596	 * High Q complex circuits require a long time to reach steady state.
597	 * To facilitate the measurement of such impedances, this mode allows
598	 * the user full control of the settling time requirement before
599	 * entering start frequency sweep mode where the impedance measurement
600	 * takes place. In this mode the impedance is excited with the
601	 * programmed start frequency (ad5933_ring_preenable),
602	 * but no measurement takes place.
603	 */
604
605	schedule_delayed_work(&st->work,
606			      msecs_to_jiffies(AD5933_INIT_EXCITATION_TIME_ms));
607	return 0;
608}
609
610static int ad5933_ring_postdisable(struct iio_dev *indio_dev)
611{
612	struct ad5933_state *st = iio_priv(indio_dev);
613
614	cancel_delayed_work_sync(&st->work);
615	return ad5933_cmd(st, AD5933_CTRL_POWER_DOWN);
616}
617
618static const struct iio_buffer_setup_ops ad5933_ring_setup_ops = {
619	.preenable = &ad5933_ring_preenable,
620	.postenable = &ad5933_ring_postenable,
621	.postdisable = &ad5933_ring_postdisable,
622};
623
624static int ad5933_register_ring_funcs_and_init(struct iio_dev *indio_dev)
625{
626	struct iio_buffer *buffer;
627
628	buffer = iio_kfifo_allocate();
629	if (!buffer)
630		return -ENOMEM;
631
632	iio_device_attach_buffer(indio_dev, buffer);
633
634	/* Ring buffer functions - here trigger setup related */
635	indio_dev->setup_ops = &ad5933_ring_setup_ops;
636
637	indio_dev->modes |= INDIO_BUFFER_HARDWARE;
638
639	return 0;
640}
641
642static void ad5933_work(struct work_struct *work)
643{
644	struct ad5933_state *st = container_of(work,
645		struct ad5933_state, work.work);
646	struct iio_dev *indio_dev = i2c_get_clientdata(st->client);
647	__be16 buf[2];
648	int val[2];
649	unsigned char status;
650
651	mutex_lock(&indio_dev->mlock);
652	if (st->state == AD5933_CTRL_INIT_START_FREQ) {
653		/* start sweep */
654		ad5933_cmd(st, AD5933_CTRL_START_SWEEP);
655		st->state = AD5933_CTRL_START_SWEEP;
656		schedule_delayed_work(&st->work, st->poll_time_jiffies);
657		mutex_unlock(&indio_dev->mlock);
658		return;
659	}
660
661	ad5933_i2c_read(st->client, AD5933_REG_STATUS, 1, &status);
662
663	if (status & AD5933_STAT_DATA_VALID) {
664		int scan_count = bitmap_weight(indio_dev->active_scan_mask,
665					       indio_dev->masklength);
666		ad5933_i2c_read(st->client,
667				test_bit(1, indio_dev->active_scan_mask) ?
668				AD5933_REG_REAL_DATA : AD5933_REG_IMAG_DATA,
669				scan_count * 2, (u8 *)buf);
670
671		if (scan_count == 2) {
672			val[0] = be16_to_cpu(buf[0]);
673			val[1] = be16_to_cpu(buf[1]);
674		} else {
675			val[0] = be16_to_cpu(buf[0]);
676		}
677		iio_push_to_buffers(indio_dev, val);
678	} else {
679		/* no data available - try again later */
680		schedule_delayed_work(&st->work, st->poll_time_jiffies);
681		mutex_unlock(&indio_dev->mlock);
682		return;
683	}
684
685	if (status & AD5933_STAT_SWEEP_DONE) {
686		/* last sample received - power down do nothing until
687		 * the ring enable is toggled */
688		ad5933_cmd(st, AD5933_CTRL_POWER_DOWN);
689	} else {
690		/* we just received a valid datum, move on to the next */
691		ad5933_cmd(st, AD5933_CTRL_INC_FREQ);
692		schedule_delayed_work(&st->work, st->poll_time_jiffies);
693	}
694
695	mutex_unlock(&indio_dev->mlock);
696}
697
698static int ad5933_probe(struct i2c_client *client,
699				   const struct i2c_device_id *id)
700{
701	int ret, voltage_uv = 0;
702	struct ad5933_platform_data *pdata = client->dev.platform_data;
703	struct ad5933_state *st;
704	struct iio_dev *indio_dev;
705
706	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st));
707	if (!indio_dev)
708		return -ENOMEM;
709
710	st = iio_priv(indio_dev);
711	i2c_set_clientdata(client, indio_dev);
712	st->client = client;
713
714	if (!pdata)
715		pdata = &ad5933_default_pdata;
716
717	st->reg = devm_regulator_get(&client->dev, "vcc");
718	if (!IS_ERR(st->reg)) {
719		ret = regulator_enable(st->reg);
720		if (ret)
721			return ret;
722		voltage_uv = regulator_get_voltage(st->reg);
723	}
724
725	if (voltage_uv)
726		st->vref_mv = voltage_uv / 1000;
727	else
728		st->vref_mv = pdata->vref_mv;
729
730	if (pdata->ext_clk_Hz) {
731		st->mclk_hz = pdata->ext_clk_Hz;
732		st->ctrl_lb = AD5933_CTRL_EXT_SYSCLK;
733	} else {
734		st->mclk_hz = AD5933_INT_OSC_FREQ_Hz;
735		st->ctrl_lb = AD5933_CTRL_INT_SYSCLK;
736	}
737
738	ad5933_calc_out_ranges(st);
739	INIT_DELAYED_WORK(&st->work, ad5933_work);
740	st->poll_time_jiffies = msecs_to_jiffies(AD5933_POLL_TIME_ms);
741
742	indio_dev->dev.parent = &client->dev;
743	indio_dev->info = &ad5933_info;
744	indio_dev->name = id->name;
745	indio_dev->modes = INDIO_DIRECT_MODE;
746	indio_dev->channels = ad5933_channels;
747	indio_dev->num_channels = ARRAY_SIZE(ad5933_channels);
748
749	ret = ad5933_register_ring_funcs_and_init(indio_dev);
750	if (ret)
751		goto error_disable_reg;
752
753	ret = ad5933_setup(st);
754	if (ret)
755		goto error_unreg_ring;
756
757	ret = iio_device_register(indio_dev);
758	if (ret)
759		goto error_unreg_ring;
760
761	return 0;
762
763error_unreg_ring:
764	iio_kfifo_free(indio_dev->buffer);
765error_disable_reg:
766	if (!IS_ERR(st->reg))
767		regulator_disable(st->reg);
768
769	return ret;
770}
771
772static int ad5933_remove(struct i2c_client *client)
773{
774	struct iio_dev *indio_dev = i2c_get_clientdata(client);
775	struct ad5933_state *st = iio_priv(indio_dev);
776
777	iio_device_unregister(indio_dev);
778	iio_kfifo_free(indio_dev->buffer);
779	if (!IS_ERR(st->reg))
780		regulator_disable(st->reg);
781
782	return 0;
783}
784
785static const struct i2c_device_id ad5933_id[] = {
786	{ "ad5933", 0 },
787	{ "ad5934", 0 },
788	{}
789};
790
791MODULE_DEVICE_TABLE(i2c, ad5933_id);
792
793static struct i2c_driver ad5933_driver = {
794	.driver = {
795		.name = "ad5933",
796	},
797	.probe = ad5933_probe,
798	.remove = ad5933_remove,
799	.id_table = ad5933_id,
800};
801module_i2c_driver(ad5933_driver);
802
803MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
804MODULE_DESCRIPTION("Analog Devices AD5933 Impedance Conv. Network Analyzer");
805MODULE_LICENSE("GPL v2");
806